docs: def _dryrun_cell(args, cell_body):
    """Implements the BigQuery cell magic used to dry run BQ queries.
  
     The supported syntax is:
     %%bigquery dryrun [-q|--sql <query identifier>]
     [<YAML or JSON cell_body or inline SQL>]
  
    Args:
      args: the argument following '%bigquery dryrun'.
      cell_body: optional contents of the cell interpreted as YAML or JSON.
    Returns:
      The response wrapped in a DryRunStats object
    """
    query = _get_query_argument(args, cell_body, datalab.utils.commands.notebook_environment())
  
    if args['verbose']:
      print(query.sql)
    result = query.execute_dry_run(dialect=args['dialect'], billing_tier=args['billing'])
    return datalab.bigquery._query_stats.QueryStats(total_bytes=result['totalBytesProcessed'],
                                                    is_cached=result['cacheHit'])